The object of entire network element signaling trace functionality of a communication system is to trace the signaling message of all User Equipments (UEs) or a specified UE in certain cell, so as to test and locate a problem and analyze the system optimization.
In related art, the process of activating and deactivating signaling trace based on management or signaling control is defined, wherein the traced object can be one or more cells or can be one or more specified UEs.
The process of activating the signaling trace of one or more cells based on management is as follows: if the signaling trace of certain cell is activated, for all the existing UEs and later accessed new UEs on the activated cell, a Node B on an evolved UMTS Terrestrial Radio Access Network (E-UTRAN Node B, or eNB) should transmit a CELL TRAFFIC TRACE message to a Mobility Management Entity (MME) and transmit the signaling to a signaling collection entity according to configured signaling trace parameters.
Meanwhile, the signaling trace of one or more specified UEs can be activated based on management or signaling; for the activating mode based on signaling, the process comprises the following scenarios:
1) an eNB receives a signaling trace start (TRACE START) message transmitted by an MME and immediately activates the signaling trace according to the signaling trace parameter configuration in the message;
2) the eNB receives an INITIAL CONTEXT SETUP REQUEST message transmitted by the MME, if the message carries a Trace Activation cell, the eNB immediately activates the signaling trace according to the signaling trace parameter configuration in the cell;
3) the eNB receives a HANDOVER REQUEST message on the X2 interface, if the message carries a Trace Activation cell, the eNB immediately activates the signaling trace according to the signaling trace parameter configuration in the cell;
4) the eNB receives a HANDOVER REQUEST message on the S1 interface, if the message carries a Trace Activation cell, the eNB immediately activates the signaling trace according to the signaling trace parameter configuration in the cell;
in which, the signaling trace configuration parameters (located in the Trace Activation cell) includes the following content:
1) E-UTRAN Trace ID, which consists of Trace Reference and Trace Recording Session Reference and uniquely identifies a trace in the E-UTRAN;
2) Interface To Trace, which indicates the interface(s) on which the signaling is to be traced, wherein the interface can be SI-MME, X2, Uu or other interfaces;
3) Trace depth, which indicates the content form of reporting signaling, including shallow layer, middle layer, deep layer, factory defined shallow layer, factory defined middle layer and factory defined deep layer;
4) Trace Collection Entity IP Address.
During the full network element signaling trace, a trace can be identified by an E-UTRAN Trace ID uniquely; for the same UE, the signaling trace start message might be received for several times. In this case, if the Trace Reference is different in the message, a new trace should be started once according to the configuration parameter in the message; as shown in FIG. 1 (in FIG. 1, the trace start message transmitted by the MME to the eNB can be the TRACE START or INITIAL CONTEXT SETUP REQUEST message); that is to say, for the same UE, there might exist a plurality of traces, for example, trace of signaling on different interfaces, use of a plurality of different signaling collection entities.
If the UE which has started the signaling trace is about to switch the X2 interface, a switched source eNB should save the current trace configuration parameter and meanwhile carry the configuration parameter in the Trace Activation cell of the HANDOVER REQUEST message to transmit to a target eNB; after receiving the message, the target eNB should immediately start the trace according to the requirement of the trace parameter so as to guarantee the continuity of trace. If the UE is about to switch the S1 interface, the MME side is responsible for entering the trace information into the Trace Activation cell of the HANDOVER REQUEST message for transmission to the target eNB; after receiving the message, the target eNB should immediately start the trace according to the requirement of the trace parameter so as to guarantee the continuity of trace.
In related art, since the Trace Activation cell of the HANDOVER REQUEST message on the X2 interface only saves one piece of trace configuration information, in the case that the UE starts a plurality of traces at the switched source eNB side, after handover, only one piece of traced information can be carried to the target eNB side and started, while other traces have to be interrupted. Likewise, during the S1 handover, since the Trace Activation cell of the HANDOVER REQUEST message on the S1 interface only saves one piece of trace configuration information too, after handover, only one piece of traced information can be carried to the target eNB side and started, while other traces have to be interrupted.
Meanwhile, in the case that the S1 connection of the UE does not exist, if the MME receives a trace configuration command transmitted by an Element Manager (EM) for the UE, the MME needs to transmit a trace start message on the S1 interface to the eNB to indicate the eNB to start the signaling trace of the UE, when the S1 logic link of the UE is established successfully. The trace start message on the S1 interface includes TRACE START and INITIAL CONTEXT SETUP REQUEST message. Since the TRACE START and INITIAL CONTEXT SETUP REQUEST messages both include a piece of trace configuration information, if the EM transmits a plurality of trace configurations (with different trace IDs) to the MME when the UE S1 link does not exist, the MME needs to transmit a plurality of trace start messages (the message can be an INITIAL CONTEXT SETUP REQUEST messages plus a plurality of TRACE START messages, or a plurality of TRACE START messages) to the eNB continuously to start the plurality of traces when the S1 link of the UE is established; in this way, the signaling interaction load of the S1 interface is increased undoubtedly.
The problem above also exists in the trace based on cell; since the CELL TRAFFIC TRACE message also carries only one set of trace configuration parameters, when a plurality of traces configured by the EM for the same cell is activated, all existing UEs and later added UEs on the activated cell need to transmit a plurality of CELL TRAFFIC TRACE messages to the MME to start all traces; in this way, the signaling interaction load of the S1 interface is greatly increased too.